Stoke Therapeutics Widens Loss as Trial Spending Climbs Ahead of NDA
Stoke Therapeutics posted a $61.6 million second-quarter net loss as research spending on its lead epilepsy drug rose 91% while collaboration revenue tied to Biogen and Acadia fell 33% to $9.3 million.
Stoke Therapeutics (STOK) reported a wider second-quarter loss as spending on its Dravet syndrome drug candidate accelerated ahead of a planned 2027 regulatory filing. The clinical-stage biotechnology company posted a net loss of $61.6 million, or $0.93 a share, compared with a net loss of $23.5 million, or $0.40 a share, in the same period last year.
The swing reflects the roll-off of a one-time payment rather than a deterioration in the underlying business. Six-month revenue fell to $15.6 million from $172.4 million in the first half of 2024, a period that included a $150.8 million non-recurring recognition tied to a Biogen intellectual-property license. With that item gone, quarterly revenue from the Acadia and Biogen collaboration agreements declined 33% to $9.3 million from $13.8 million a year earlier. Six-month results flipped from net income of $89.4 million, or $1.50 diluted a share, in the first half of 2024 to a net loss of $111.6 million, or $1.73 a share, in the first half of 2025.
Research and development expense rose 91% to $49.5 million in the quarter from $25.9 million a year earlier, attributed to increased activity and personnel supporting its lead drug candidate, zorevunersen, as it moves through Phase 3 testing and toward regulatory filing preparation. Selling, general and administrative expense climbed 65% to $25.3 million from $15.3 million, driven by staffing growth and spending tied to commercial launch readiness.
The spending increase corresponds with a Phase 3 trial that finished enrollment ahead of its original target. The EMPEROR study completed enrollment of 162 patients by the end of June, above the 150-patient goal set in January. Stoke disclosed patient-level progression detail for the first time: roughly 145 patients have passed the Week 8 mark, 80 have passed Week 24, and 60 have passed Week 28 as of July 31, up from about 50 patients through Week 28 as of the June update. The Chief Executive highlighted zero treatment discontinuations to date as the first patients approach the Week 52 completion milestone, expected this month.
Guidance on the trial's data readout slipped modestly even as enrollment ran ahead of schedule. Stoke had guided to a data readout in "mid-2027" as recently as May; the anchor release specifies "Q3 2027". At the same time, guidance for initiating a rolling regulatory submission narrowed from "first half 2027" in January to a firmer "Q1 2027" in the May, June and August releases.
Stoke also disclosed progress in a separate early-stage program, OSPREY, testing STK-002 in autosomal dominant optic atrophy. The first cohort of three patients has been fully dosed with no serious or severe safety events reported, and dosing of a second cohort is set to begin in August, an advance from the prior quarter when all eight trial sites were active but dosing had not yet started. Thomas McCauley joined as chief scientific officer in July. Enrollment for an additional EMPEROR cohort in China is now described as underway, with completion anticipated in the second half of 2025, an update from the prior quarter's language describing only site activation.
Stoke ended the period with $420.0 million in cash, cash equivalents and marketable securities on a pro forma basis as of August 3, up from $411.0 million at the end of March, aided by a $65.7 million at-the-market sale to a single investor after quarter-end that followed an $80.7 million ATM raise earlier in the year. The company has said the balance is intended to fund operations through commercialization in early 2028, a runway that continues to depend on additional stock issuance under the ATM program.